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Viewing Multicast Demands in the Network

  1. At this point, a multicast group has been defined and demands, or flows, to the multicast group have been created. Now, information on these demands and how they fit into the network can be examined. Select Update Demand Routing Tables and click Yes when prompted.

  2. The first thing to notice is that, even though there are multiple recipients of the 100M flows from node SFO, the link utilization appears uniform throughout all the utilized links, as shown in Figure 1. This is typical of multicast networks and is a good example of the advantage of multicast over traditional unicast networks. In traditional unicast networks, one would expect “high” utilization near the source and “lower” utilization as the flows fan out to the recipients. Here, the utilization is “low” everywhere.

    Figure 1: Link Utilization in a Multicast NetworkNetwork topology map showing nodes connected by links. Red indicates high utilization, green moderate, and blue low. Top right text mentions 18 OC3 cost=187730.

  3. Now, click on Network > Elements > Demands. The Demands window lists all the demands in the network, which in this example should all be multicast demands.

  4. Highlight any of the rows in the demands table and click the Show Path button. This will display the path taken by the demand according to the unicast protocol being used. The default protocol is PIM-SM (Protocol Independent Multicast - Sparse Mode). This can be changed for each demand by modifying the demand’s Type field.

    Figure 2: Path of a Demand from SFO to BOSNetwork diagram showing nodes and color-coded lines indicating link utilization from 0.0% blue to 100.0% red. Includes cost calculation: 18 OC3 cost equals $187730.

  5. Detailed information on link utilization resulting from the multicast demands can be viewed through the Peak Link Utilization Report under Simulation Reports > Network StatisticsTo do this, click on Report > Report Manager, then select Peak Link Utilization from the list of reports in the Report Manager window. Notice in the example below that all the utilized links display a utilization of 100M.

    Figure 3: Link Peak Utilization Report for a Multicast NetworkReport Manager software screenshot showing Link Peak Utilization Report in a table with network link data including names, locations, and utilization percentages.

  6. Select Subviews > Multicast from the map to view the multicast tree graphically.

    Figure 4: Multicast SubviewNetwork topology map showing nodes with city abbreviations like SFO and NYC connected by color-coded lines indicating link status. Includes Autonomous System label AS65002 within a network monitoring interface with multicast information on the left.

  7. Note the special icons used for the source (SFO), the Rendezvous Point (WDC) and the subscribers.

  8. If there are multiple trees listed, you can <Ctrl>-click to highlight multiple trees at once. Each multicast tree will have a different color, e.g., yellow, green, blue. Overlaps between trees will also have a unique color, e.g., orange.